• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.4
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• pp.343-352
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• 2012

In order to precisely determine the vertical displacements of CORS antenna phase centers caused by their replacement, intensive research has been carried out in this paper throughout processing GPS measurements made before and after the events. After applying the estimated displacement in the data processing, results show that coordinate repeatability of the vertical component is able to be 7.9mm on average. Comparing with results (e.g., 23.5mm) without applying the displacement, it was possible to conclude that these accuracies are significantly improved, which is equivalent to those before the event of the replacement.

• Journal of Cadastre & Land InformatiX
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• v.51 no.1
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• pp.125-136
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• 2021

Recently, Unmanned Aerial Vehicle utilization and image processing technology for remote sensing have diversified remarkably with Orthophoto and Digital Surface Model. In particular, It uses more application fields such as spatial information analysis and hazardous areas as well as land surveying. This study analyses the accuracy of the coordinate on Orthophoto and DSM height on slope area with high and low differences by using UAV images. As the result of this study, in the case of GCP on 2D orthophoto, the location error was not produced significantly. The vertical position of the DSM showed the highest accuracy when the height difference between GCPs is under 30m(RMSEZ=0.07m). The location of the GCPs was divided into approximately 10m, 20m, 30m, and 40m with analysis for each of the eight points of GCP and inspection points in general. This study expects that producing both horizontal accuracy of Orthophoto and vertical accuracy of DSM using UAV on the sloped area which similar to this research area will help in spatial information fields.

• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.4
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• pp.54-63
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• 2013

In this paper, we evaluate the accuracy of the vertical positioning by distance using Network RTK-GPS. The experimental results confirm that Network RTK-GPS method can acquire data quickly and accurately than conventional leveling methods so that the Network RTK-GPS method is a relatively efficient and economical way for the vertical positioning. Results of validation using permanent GPS stations indicate that visible satellites, PDOP, and VDOP are very good for the vertical positioning. Integrated reference points such as U0997 and U0921 are satisfied with 3 ratings in the rules of public leveling and all the rest are proved improper. When the vertical positioning using Network RTK-GPS is implemented, the geoid height of EGM2008 should be applied for leveling. If the number of geodetic satellite are increasing in the near future, the vertical positioning using Network RTK-GPS can be possible in all the range.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.210-213
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• 1999

수동소나체계에서 음원의 위치와 관련된 매개변수를 산출하기 위해 정합장처리(Matched Field Processing)가 이용된다 본 연구에서는 수직선배열센서를 이용한 정합장처리에서 음원 위치추정에 영향을 미치는 다양한 요인 중, 수직음속분포 오정합(mismatch)에 의한 영향을 MV 프로세서 (Minimum Variance Processor)를 이용하여 모의실험함으로써 그 결과를 분석하였다. 천해 모의환경에서 동일한 기울기로 증감하는 수직음속분포 오정합은 음원 위치추정에서 거리성분의 오차를 가지며, 상이한 기울기를 갖는 수직음속분포 오정합은 거리와 수심 성분의 오차가 유발됨을 확인할 수 있었다. 심해 모의 환경에서 수직음속분포 오정합은 거리와 수심 성분의 오차가 유발되고, 거리추정의 전반적인 경향은 천해의 동일한 기울기를 가지는 경우와 유사함을 확인할 수 있었다.

• Journal of Advanced Navigation Technology
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• v.25 no.1
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• pp.8-16
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• 2021

In this paper, locations of vertiports were selected and evaluated to operate urban air mobility (UAM) in the Seoul metropolitan area. Demand data were analyzed using the data from the survey of commuting population and were marked on a map using MATLAB. To cluster the data, the K-means algorithm function built in MATLAB was used to identify the center of the cluster to as the location of vertiports, and using the silhouette technique, the accuracy and reliability of the clustering were evaluated. The locations of the selected vertiports were also identified using satellite maps to ensure that the locations of the selected vertiports were suitable for the actual vertiport location, and, if the location was not appropriate, final vertiports were selected through the repositioning process.

• Proceedings of the Korea Contents Association Conference
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• 2012.05a
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• pp.431-432
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• 2012

상수도관의 노후화에 따라 빈번히 발생하는 상수관망의 용수공급 중단의 피해를 저감하고 관망내에서 발생하는 용수의 수질저하를 방지하기 위하여 용수공급 블록단위에 소규모의 수직형 정수처리 시설을 설치하는 방안이 연구되고 있다. 이와 같이 설치되는 수직형 정수처리 시설을 기존 관망내에 적절한 위치에 설치하여야 최대의 효과를 가져올 수 있다. 이를 위하여 EPANET을 활용하여 수직형 정수처리 시설을 다양한 지점에 설치한다고 가정한 후 개별 설치지점별 수리학적 안정성을 절점의 압력변동폭으로 정량화하여 최적위치를 결정할 수 있는 방법을 제안하였다. 제안된 방법을 국내 A 관망에 적용하여 적용성을 검증하였다.

• The korean journal of orthodontics
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• v.31 no.4 s.87
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• pp.425-438
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• 2001

The delivery of optimal orthodontic treatment is greatly influenced by clinician's ability to predict and control tooth movement by applying well-known force system to dentition. It is very important to determine the location of the centers of resistance of a tooth or teeth in order to have better understanding the nature of displacement characteristics under various force levels. In this study, three dimensional finite element analysis was used to measure the initial displacement of the consolidated teeth under loading. The purpose of this study was to define the location of the centers of resistance at the upper six anterior segment. To observe the changes of six anterior segment, 200gm, 250gm, 300gm, and 350gm forces at right and left hand side each were imposed toward lingual direction. For this study, two cases, six anterior teeth and six anterior teeth after corticotomy, were reviewed. In addition, it was reviewed the effects of changes on the location of the center of resistance in both cases based on different degree of forces aforementioned. The results were that : 1. The instantaneous center of resistance for the six anterior teeth was vertically located between level 4 and level 5, which is, at 6.76mm, $44.32\%$ apical to the cementoenamel junction level. 2. The instantaneous center of resistance for the six anterior teeth after corticotomy was located vertically between level 4 and level 5, that is, at 7.09mm $46.38\%$ apical to the cementoenamel junction level. 3. Changes of force showed little effect on the location of the center of resistance in each case. 4. It was observed that the location of the instantaneous center of resistance for the six anterior teeth after corticotomy was changed more than the six anterior teeth without corticotomy to the apical part, and the displacement of the consolidated anterior teeth moved further in case of the consolidated teeth after corticotomy.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.19 no.2
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• pp.155-161
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• 2001

When determining a three dimensional position for engineering purposes, we can use the GPS survey to find position. According to the enhancement of precision for domestic Geoid model, the positional accuracy of GPS about precise method of vertical position has been also increased. But by considering Geoid undulation, it is difficult to measure GPS-derived elevations. Because Geoid undulation has changed little in local sites, GPS-derived elevations are similar to orthometric height. By ignoring Geoid undulation, it is possible to measure GLT-derived elevations at the local. small construction sites. GLT(GPS Leveling Technique) provides a method for computing orthometric heights. GLT processes the data more rapidly than conventional measurement devices. We only considered the weight factors affecting accuracy between the points. That is, the GPS procedures to produce satisfactory elevation accuracy depends on the method of observations, receivers and conditions of the local environment. A comparison was performed between the GPS survey using Geoid model and GLT at a part within Pusan National University and construction model sites in South Korea. And the writers proved the GPS surveying is efficient in positioning accuracy, time, and cost on a construction sites.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.4
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• pp.393-400
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• 2020

Axial and lateral behavior of helical piles is generally influenced by number, diameter, helix pitch, and locations of helices. In this study, axial and horizontal behavior of helical piles with three helices was investigated varying helices' locations, diameter, and pitch. Especially, due to the spiral shapes of helices, the effect of lateral load directions at pile heads on their lateral behavior was investigated. Axial load test of small-scale helical pile was conducted in laboratory, and its results were compared with numerical analysis results of the same model for cross check of validity of both results. Furthermore, diverse numerical analyses were performed for different shapes of helical piles. Consequently, it was found that, for the given analysis conditions, the helix diameter was the most influential factor on the horizontal and vertical behavior of helical piles.

• 한국공간정보시스템학회:학술대회논문집
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• 2005.11a
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• pp.75-79
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• 2005

최근에 모바일 기기의 급속한 발전과 더불어 다양한 서비스들이 개발되고 있다. 그 중에서도 위치 기반 서비스는 사용자에게 위치와 관련된 유용한 정보를 제공하는 서비스를 말한다. 효과적인 서비스를 제공하기 위해서는 먼저 위치정보를 나타내는 이동 객체 관련기술 연구가 선행되어야 한다. 이러한 연구의 핵심 기술로 현재 빈발한 이동 객체 탐사를 위한 마이닝 기법들에 관한 연구가 진행되고 있다. 본 연구에서는 기존의 수평적 마이닝 기법에서 문제시되었던 많은 후보 이동 객체 발생을 줄이기 위해 새로운 수직적 마이닝 기법을 적용한 방법을 제안한다.